The invention relates to a machine for packaging fragile cylindrical products, particularly cigarettes or similar, comprising:
a unit for feeding a succession of ordered groups of cigarettes; PA1 a drum for folding wrapping slips around a group of cigarettes, this drum being provided with at least one and preferably more peripheral cells, each of which houses one group of cigarettes and has a peripheral opening for the insertion of a group of cigarettes; PA1 a station for joining a wrapping slip to a group of cigarettes, in which station the group of cigarettes is disposed in a position coinciding with and in front of the open side of the associated cell and the wrapping slip is interposed between the open insertion side of the cigarette-carrying cell and the facing side of the group of cigarettes; PA1 means of collecting the wrapping slip and positioning it in a predetermined position, substantially parallel to the facing sides of the group of cigarettes and of the cigarette-carrying cell; PA1 means of gripping the group of cigarettes and inserting it, together with the wrapping slip, into the cigarette-carrying cell; PA1 means of transferring the group of cigarettes from the unit for feeding the succession of groups of cigarettes to the station for joining them to the wrapping slips; PA1 means of synchronized operation of the said feed unit and the said collecting/positioning, gripping/inserting and transferring means. PA1 the means of collecting and positioning the wrapping slips have at least two pairs of gripping suction fingers which are supported movably together along an annular path about at least one axis parallel to the axis of the folding drum, and which have a fixed relative disposition such that each of them interacts with one lateral face of the slip at one of the front and rear ends of the slip with respect to the direction of movement of the fingers along the annular path; PA1 the means of transferring the cigarettes from the feed unit to the joining station are made in such a way that the transfer path of the groups of cigarettes is at least partially rectilinear.
The object of the invention is to provide a packaging machine of the type described initially, in such a way that a high operating speed can be provided without the necessity of excessively large drive motors, while ensuring simpler and less costly construction and reliable operation, with the reduction of the inertial masses and the feed movements for transferring the ordered groups of cigarettes and allowing a greater and more rapid adaptability of the machine to the different standard dimensions of cigarettes and of the ordered groups of cigarettes.
The invention achieves the objects stated above with a packaging machine for fragile cylindrical products of the type described initially, in which:
In one embodiment, the rectilinear transfer path of the groups of cigarettes is transverse with respect to the axis of the path of the gripping suction fingers, and is a secant of this axis.
According to a further characteristic, the gripping fingers are fitted on guide and support means which laterally surround an intermediate transfer channel interposed between the fingers associated with the two opposite lateral strips of the wrapping slips; this transfer channel opens onto the open insertion sides of the cigarette-carrying cells at the joining station, and is orientated in the direction of insertion of the groups of cigarettes together with the wrapping slips into the said cells, while the transfer channel is associated with linear transfer elements which are moved along the said transfer channel, with a reciprocating motion along an annular rectangular path, in other words with rectilinear transfer and return movements and transverse raising and lowering movements.
The rectilinear transfer path of the groups of cigarettes is advantageously coplanar, and laterally out of alignment, with the transport path of the groups of cigarettes on the feed unit, pushing means being provided to move the groups of cigarettes from the discharge end of the feed unit to the entry end of the transfer channel along a path transverse with respect to the transfer channel and to the direction of transport of the cigarettes on the feed unit.
The entry end of the transfer channel is disposed substantially in the median area of the annular path of the gripping fingers, the guide and support means of the gripping fingers consisting, at least on the side facing the feed unit, of an annular member coaxial with the annular path of the fingers, the said annular member being supported on a stationary annular guide which has a central aperture for the passage of the groups of cigarettes from the discharge end of the feed unit to the entry end of the transfer channel.
The annular path of the gripping fingers is preferably circular, and the transfer path of the cigarettes, in other words the movement of the transfer elements and the transfer channel may be orientated substantially radially with respect to the circular path of the gripping fingers, and may advantageously extend from the central area of the circular annular path of the gripping fingers to the area which is radially directly behind the gripping fingers at the joining station with reference to the direction of transfer.
In a preferred embodiment, the paths of the groups of cigarettes on the feed unit, in the transfer channel and at the point of insertion together with the slips into the cells of the folding drum are contained within the same horizontal plane, while the cigarettes are orientated with their axes transverse with respect to the direction of movement along the said paths and parallel to the axis of the circular path of the gripping suction fingers. Additionally, the insertion movement of the groups of cigarettes together with the wrapping slips consists of a coaxial continuation of the transfer movement, and the passage from the feed unit to the linear transfer means takes place in the direction of the axis of the cigarettes.